Eukaryota Chatton, 1925 - eukaryotes see Domain Eukaryota Chatton, 1925
   Opisthokonta Cavalier-Smith, 1987 - opisthokonts see Clade Opisthokonta Cavalier-Smith 1987, nom. cl. inval.
     Metazoa Haeckel 1874 - multicellular animals see Kingdom Animalia Linnaeus, 1758
       Eumetazoa Bütschli, 1910 - eumetazoans
         Triploblastica see [unranked] Bilateria Hatschek, 1888
           Bilateria Hatschek, 1888 - bilaterians see Subkingdom Bilateria Hatschek, 1888
             Protostomia Grobben, 1908 see Infrakingdom Protostomia Grobben, 1908
               Lophotrochozoa Halanych, Bacheller, Aguinaldo, Liva, Hillis & Lake 1995 - lophotrochozoans
                 Spiralia Schleip, 1929 - spiralians see Superphylum Spiralia Schleip, 1929
                   Trochozoa Beklemischev, 1944 - trochozoans
                     Phylum Mollusca Linnaeus, 1758 - molluscs
                       Eumollusca
                         Conchifera Gegenbaur, 1878 see Subphylum Conchifera Gegenbauer, 1878
                           Ganglioneura Rudophi, 1812
                             Ancyropoda see [unranked] Conchifera Gegenbaur, 1878
                               Class Bivalvia Linnaeus, 1758 - bivalves
                                 Subclass Metabranchia see Subclass Autobranchia Grobben, 1894
                                   Superorder Eulamellibranchia see Superorder Heteroconchia Gray, 1854
                                     Order Unionida Gray, 1854
                                       1 Family Unionidae Rafinesque, 1820 - pearly mussels
                                       2 Family Margaritiferidae Henderson, 1929 (1910), nom. cons. - freshwater pearl mussels
                                       3 Family Mutelidae Gray, 1847 see Subfamily Iridininae Swainson, 1840
                                       4 Family Etheriidae Deshayes, 1832 - freshwater oysters
                                       5 Family Hydriidae orth. inval. see Family Hyriidae Swainson, 1840